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Abstract:

A cathode including an active material composite and a lithium battery
using the same. The active material composite of the cathode includes a
mixed oxide complex and a lithium-containing compound, the
lithium-containing compound having a metal based compound coated on the
surface of the lithium-containing compound.

Description:

[0001]This application claims the benefit of Korean Application No.
2007-57441, filed Jun. 12, 2007 in the Korean Intellectual Property
Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]Aspects of the present invention relate to a cathode comprising an
active material composite and to a lithium battery using the same, and
more particularly, to a cathode comprising an active material composite
that can improve electrode performance by improving the conductivity
characteristics during initial charging/discharging cycles, and to a
lithium battery using the same.

[0004]2. Description of the Related Art

[0005]In general, transition metal compounds such as LiNiO2,
LiCoO2, LiMn2O4, LiFePO4,
LiNixCo1-xO2(0<x<1) and
LiNiyMnyCo1-2yO2(0<y<0.5), and oxides of these
compounds and of lithium are widely used as cathode active materials for
lithium batteries. Recently, various composite oxides have been proposed
as alternatives to address the ever increasing demand for higher capacity
batteries.

[0006]One such composite oxide, xLi2MO3-(1-x)LiMeO2, is a
solid-solution complex of Li2MO3 and LiMeO2where M is a
group of metal elements including at least one of Mn, Zr, and Ti, and Me
is a group of metal elements including at least one of Ni, Co, Mn, Cr,
Fe, V, Al, Mg, and Ti. The complex, which is a solid-solution, has a
layered structure, with respective layers of Li2MO3 and
LiMeO2, where excess lithium is substituted in a transition metal
layer.

[0007]For example, in the case of the solid-solution complex component,
Li2MO3, where manganese (Mn) is used as the transition metal M,
Mn has an oxidation number of +4 during the charge cycle but the
oxidation number of Mn in the oxygen layer is between +4 or +5, thus not
permitting Mn to contribute to electric conductivity. In addition, if a
battery has a capacity high enough to be feasible, lithium accounts for
approximately 10 to 20 atomic percent of the composition of the
transition metal layer. Because of the excess of lithium, Mn predominates
at more than two times the content of lithium. Thus, the proportion of
transition metals actually contributing to electric conductivity, e.g.,
Ni, Co, or the like, is restricted, resulting in a reduction in the
electric conductivity of the cathode active material. Accordingly, in
order to effectively utilize the xLi2MO3-(1-x)LiMeO2
complex as a cathode active material, a need exists to solve the problem
associated with electric conductivity of the complex.

SUMMARY OF THE INVENTION

[0008]Aspects of the present invention provide a cathode comprising a
cathode active material having improved conductivity while using a
xLi2MO3-(1-x)LiMeO2 complex. Aspects of the present
invention also provide a lithium battery using the cathode active
material.

[0009]Another aspect of the present invention, provides a cathode
including an active material composite, a complex represented by Formula
1, and a lithium-containing compound represented by Formula 2, the
lithium-containing compound having a metal based compound coated on its
surface, wherein

[0010]Formula 1 is xLi2MO3-(1-x)LiMeO2

[0011]0<x<1, and M and Me are the same or different metal ions,
wherein

[0014]In one embodiment, in the complex represented by Formula 1, Me is
preferably at least one metal selected from the group consisting of
nickel (Ni), cobalt (Co), manganese (Mn) and chromium (Cr). In another
embodiment, in the complex represented by Formula 1, M is preferably at
least one metal selected from the group consisting of manganese (Mn),
titanium (Ti) and Zr (zirconium). In another embodiment, in the complex
represented by Formula 1, x preferably ranges from 0.1 to 0.6.

[0015]In another embodiment, the content of the lithium-containing
compound represented by Formula 2 is preferably 1 to 60 wt % relative to
the total weight of the cathode active material. In another embodiment,
the content of the lithium-containing compound represented by Formula 2
is more preferably 3 to 50 wt % relative to the total weight of the
cathode active material.

[0016]In another embodiment, in Formula 2, the metal based compound of the
surface coating is preferably a metal oxide or a metal phosphate. In
another embodiment, in Formula 2, the metal oxide is preferably at least
one selected from the group consisting of Al2O3, MgO,
SiO2, CeO2, ZrO2 and ZnO.

[0017]Additional aspects and/or advantages of the invention will be set
forth in part in the description which follows and, in part, will be
obvious from the description, or may be learned by practice of the
invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]These and/or other aspects and advantages of the invention will
become apparent and more readily appreciated from the following
description of the embodiments, taken in conjunction with the
accompanying drawings of which:

[0019]FIG. 1 is a graph illustrating current density expressed as capacity
per weight (mAh/g) and capacity ratio as functions of various mixture
ratios of Li1.2Ni0.133Co0.133Mn0.534O2 and
Al2O3-coated LiCoO2 according to Examples 1 through 4 of
aspects of the present invention and Comparative Examples 1 and 2;

[0020]FIG. 2 is a graph illustrating f current density expressed as
capacity per volume (mAh/cc) as a function of various mixture ratios of
Li1.2Ni0.133Co0.133Mn0.534O2 and
Al2O3-coated LiCoO2 according to Examples 1 through 4 of
aspects of the present invention and Comparative Examples 1 and 2; and

[0021]FIG. 3 illustrates the percentage of capacity retention after 50
cycles as a function of various mixture ratios of
Li1.2Ni0.133Co0.133Mn0.534O2 and
Al2O3-coated LiCoO2 according to Examples 1 through 4 of
aspects of the present invention and Comparative Examples 1 and 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022]Reference will now be made in detail to the present embodiments of
the present invention, examples of which are illustrated in the
accompanying drawings. The embodiments are described below in order to
explain the present invention by referring to the figures.

[0023]Aspects of the present invention are characterized in that they
provide a cathode comprising an active material composite that can
improve electrochemical characteristics by adding a complex material to a
lithium-containing compound having excellent conductivity and
high-voltage stability. The active material composite according to these
aspects include a complex represented by Formula 1, and a
lithium-containing compound represented by Formula 2, the
lithium-containing compound having a metal based compound coated on its
surface, wherein:

[0024]The complex represented by Formula 1, which is a solid-solution,
exhibits the same layered structure as each of the two components
Li2MO3 and LiMeO2, and exists in a form in which excess
lithium is substituted in a transition metal layer.

[0025]In the complex represented by Formula 1, x defines the molar ratio
of two components Li2MO3 and LiMeO2, x being in the range
between 0 and 1, preferably in the range between 0.1 and 0.6. In
addition, M is at least one metal selected from the group consisting of
manganese (Mn), titanium (Ti) and Zr (zirconium) and Me is at least one
metal selected from the group consisting of nickel (Ni), cobalt (Co),
manganese (Mn) and chromium (Cr).

[0026]The complex represented by Formula 1 used for the cathode active
material according to this aspect of the present invention can be
prepared by combustion synthesis. For example, a starting material in the
form of a metal salt, e.g., carbonate, or acetate, is dissolved in an
acidic solution to form a sol, and evaporated to remove moisture,
yielding a gel, followed by combustion and post heat-treatment, thereby
preparing a powder of the desired complex represented by Formula 1.
Alternatively, the complex represented by Formula 1 can be prepared by a
hydrothermal process under basic conditions using LiOH and/or KOH. Such
processes are undertaken in a pressurized autoclave, preferably between 5
and 35 atmospheres and at temperatures ranging between 100 and
150° C. for about 6 to 12 hours or more.

[0027]Details as to the preparation process and physical properties of the
complex represented by Formula 1 are disclosed in U.S. Pat. No. 6,677,082
and U.S. Published Application No. 2006/0051673, the disclosures of which
are incorporated herein in their entirety by reference.

[0028]When the complex represented by Formula 1 is used as the cathode
active material, a battery manufactured using the same may demonstrate
reduced conductivity while providing high capacity. Therefore, aspects of
the present invention provide a cathode active material having improved
electrochemical characteristics by improving the conductivity
characteristic using a cathode active material in the form of a
combination or a complex containing the lithium-containing compound
represented by Formula 2, which compound has excellent conductivity.

[0029]In order to impart a high capacity to the complex represented by
Formula 1, lithium cells should be charged during an initial charge cycle
at a high voltage of up to 4.5 V relative to Li. Oxidation of oxygen
atoms at approximately 4.5 V during the initial charge cycle removes
lithium ions from the composite, and after the initial charge cycle, a
reversible reaction is carried out by a redox reaction of a metal
contained in the composite, e.g., manganese. Accordingly, the
lithium-containing compound represented by Formula 2 added for improving
the conductivity is preferably a material demonstrating high-voltage
stability at approximately 4.5 V.

[0030]To this end, it is beneficial to control reactivity of the
lithium-containing compound represented by Formula 2 with respect to an
electrolyte by surface-coating so as to allow the lithium-containing
compound represented by Formula 2 to withstand a high voltage. In order
to achieve this, according to aspects of the present invention, the
surface of the lithium-containing compound represented by Formula 2 is
coated with a metal based compound, thereby protecting the
lithium-containing compound represented by Formula 2 at high-voltage.
That is to say, the lithium-containing compound coated with the metal
based compound demonstrates an improved structural stability by
minimizing any anisotropic volume change due to intercalation/removal of
lithium ions during charge/discharge cycles, thereby improving the cycle
life of the battery at high-voltage.

[0031]Examples of the metal based compound used in surface coating for
protecting the surface of the lithium-containing compound represented by
Formula 2 include metal based oxides, metal based phosphates, and the
like. Useful examples of the metal based oxides include, but are not
limited to, at least one selected from the group consisting of
Al2O3, MgO, SiO2, CeO2, ZrO2 and ZnO. Useful
examples of the metal based phosphates include, but are not limited to,
AlPO4.

[0032]A coating solution including at least one coating element is used in
coating the cathode active material according to an aspect of the present
invention. The coating solution is obtained by dissolving an alkoxide,
salt or oxide containing the coating element in an organic solvent, and
preferably refluxing the resulting mixture. Useful examples of the
organic solvent include alcohols (such as methanol, ethanol or
isopropanol), hexane, chloroform, tetrahydrofuran, ether, methylene
chloride, or acetone. Throughout this specification, the term "coating
solution" is used to mean both a solution and a homogenous suspension.

[0033]The coating is performing by adding the lithium-containing compound
represented by Formula 2 to the coating solution prepared in the
above-described manner. The simplest coating process is dip coating, but
any other coating techniques such as a spray method, a sol-gel method, or
the like, can be used. Coating of the metal based compound on the
lithium-containing compound represented by Formula 2 may be carried out
in either a non-continuous process or a single continuous ("one-shot")
process.

[0034]The coated lithium-containing compound represented by Formula 2 is
heat-treated to prepare a cathode active material having a surface coated
with the metal based compound. The heat-treating process is preferably
performed at a temperature ranging from 300 to 800° C. for 3 to 10
hours. Prior to the heat-treating process, a drying process may be
further performed at a temperature ranging from 80 to 200° C. for
1 to 5 hours. When the heat-treatment temperature is lower than
300° C., discharge and lifespan improving effects for the battery
are not exhibited. When the heat-treatment temperature is higher than
800° C., a poor coating is formed, undesirably, at the surface of
the active material.

[0035]Details as to a preparation process and physical properties of the
lithium-containing compound represented by Formula 2 are disclosed in
U.S. Pat. Nos. 6,753,111 and 6,916,580, the disclosures of which are
incorporated herein in their entirety by reference.

[0036]When the complex represented by Formula 1 and the lithium-containing
compound represented by Formula 2 having a surface coated with the metal
based compound are used as cathode active materials, these materials may
first be pulverized to a predetermined particle size and then mixed
before use. Alternatively, these materials may first be mixed together
and then pulverized before use. In either case, an average particle size
of the complex represented by Formula 1 is preferably not greater than 10
μm and also an average particle size of the lithium-containing
compound represented by Formula 2 is preferably not smaller than 10
μm.

[0037]A process of manufacturing a lithium battery using the complex
represented by Formula 1 and the lithium-containing compound represented
by Formula 2 having a surface coated with the metal based compound used
as cathode active materials, will now be described. First, a cathode
active material, a conducting agent, a binder, and a solvent are mixed
together to prepare a cathode active material composition. The cathode
active material composition is directly coated on an aluminum current
collector and dried to form a cathode plate. Alternatively, the cathode
plate may be manufactured by laminating an aluminum current collector
with a cathode active material film that has previously been formed by
casting the cathode active material composition on a support and then
separating the composition from the support.

[0038]As the conducting agent, carbon black can be used. Nonlimiting
examples of suitable binders include
vinylidenefluoride/hexafluoropropylene copolymers, polyvinylidenefluoride
(PVDF), polyacrylonitrile, polymethylmethacrylate,
polytetrafluoroethylene and mixtures thereof. Styrene butadiene rubber
polymers may also be used as the binder. Nonlimiting examples of suitable
solvents include N-methyl-pyrrolidone, acetone, water and the like. The
cathode active material, the conducting agent, the binder and the solvent
are used in amounts commonly used in lithium batteries.

[0039]In a similar manner to manufacture of the cathode plate, an anode
active material, a conducting agent, a binder, and a solvent are mixed to
prepare an anode active material composition. An anode plate is then
prepared by directly coating the anode active material composition onto a
copper foil and drying the anode active material composition.
Alternatively, the anode active material composition is cast on a
separate support to form an anode active material film, which is then
released from the support and laminated onto the copper current
collector. The anode active material, the conducting agent, the binder
and the solvent are used in amounts commonly used in lithium batteries.

[0040]Examples of the anode active material include lithium metals,
lithium alloys, carbonaceous materials, graphite, and the like. The same
conducting agent, binder and solvent as those used in the cathode active
material composition may be used in the anode active material
composition. In one embodiment, a plasticizing agent may be further added
into each of the cathode and anode active material compositions to form
porous cathode and anode plates.

[0041]The cathode and the anode can be insulated from each other by a
separator. Any separator commonly used in the manufacture of lithium
batteries may be used as the separator. Particularly, preferred materials
for the separator should have low resistance to ion movement of the
electrolyte and good electrolyte impregnation properties. Specific
examples of such separator materials include glass fiber, polyester,
polyethylene, polypropylene, polytetrafluoroethylene (PTFE), and a
combination of the foregoing materials, which may be in non-woven fabric
or woven fabric form. As will now be described in greater detail. In the
case of a lithium ion battery, a rolled separator made of polyethylene,
polypropylene and the like, are used. Also, in the case of a lithium ion
polymer battery, a separator having good electrolyte impregnation
properties is used. These separators may be manufactured in the following
manner.

[0042]First, a polymer resin, a filling agent, and a solvent are mixed
together to prepare a separator composition. This separator composition
is directly coated on an electrode and dried to form a separator.
Alternatively, the separator may be formed by laminating the electrode
with the separator, which is previously formed by casting the separator
composition on a support and drying.

[0043]Any polymer resin that can be used as a binder for electrode plates
may be used without limitation. Examples of the polymer resin include a
polyvinylidenefluoride-hexafluoropropylene copolymer, PVDF,
polyacrylonitrile, polymethacrylate, and a mixture of the foregoing
materials. A preferred polymer resin is a
vinylidenefluoride-hexafluoropropylene copolymer containing 8 to 25% by
weight of hexafluoropropylene. Examples of the binder include
PVDF-hexafluoropropylene copolymer, polyvinylidenefluoride,
polyacrylonitrile, polymethymethacrylate, and mixtures thereof.

[0044]The separator is disposed between the cathode plate and anode plate
manufactured as described above to form an electrode assembly. This
electrode assembly is wound or folded and then sealed in a cylindrical or
rectangular battery case. Next, the organic electrolytic solution
according to aspects of the present invention is injected into the
battery case so that a complete lithium secondary battery is obtained.

[0045]Alternatively, the electrode assembly may be stacked to form a
bi-cell structure, which is then impregnated with the organic electrolyte
solution and the resulting structure is sealed in a pouch, thereby
obtaining a completed lithium ion polymer battery. An organic electrolyte
solution for the lithium battery includes a lithium salt, and a mixed
organic solvent consisting of a high dielectric constant solvent and a
low boiling point solvent.

[0046]Any high dielectric constant solvent commonly used in the art may be
used without limitation according to these aspects of the present
invention and specific examples thereof include cyclic carbonates such as
ethylene carbonate, propylene carbonate, or butylene carbonate, and
y-butyrolactone. Further, the low boiling point solvent is also commonly
used in the art and nonlimiting examples thereof include carbonates such
as dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate,
dipropyl carbonate, dimethoxyethane, diethoxyethane, fatty acid ester
derivatives, and the like.

[0047]The high dielectric constant solvent and the low boiling point
solvent are preferably mixed in a ratio of 1:1 to 1:9 by volume. If the
volumetric ratio of the low boiling point solvent to the high dielectric
constant solvent does not fall within the stated range, the lithium
battery demonstrates undesirable characteristics of low discharge
capacity, too few charge/discharge cycles and short lifespan.

[0048]In addition, the lithium salt is not particularly limited, provided
that it is generally used for a lithium battery, and is preferably at
least one selected from the group consisting of LiClO4,
LiCF3SO3, LiPF6, LiN(CF3SO2)2, LiBF4,
LiC(CF3SO2)3, and LiN(C2F5SO2)2. The
concentration of the lithium salt is preferably in the range of 0.5 to
2.0 M. If the concentration of the lithium salt is less than 0.5 M, the
ionic conductivity of the electrolytic solution decreases, so that the
performance of the electrolytic solution may be degraded. If the
concentration of the lithium salt is greater than 2.0 M, the viscosity of
the electrolytic solution increases, so that mobility of lithium ions is
undesirably reduced.

[0049]Aspects of the present invention will now be described using the
following examples. However, it is understood that the following examples
are illustrative in nature and that the present invention is not limited
thereto.

COMPARATIVE EXAMPLE 1

[0050]Only sub-micron sized
Li1.2Ni0.133Co0.133Mn0.534O2, which is prepared
by combustion synthesis, was used as a cathode active material. The
cathode active material and a carbon conducting agent (KETJENBLACK®
EC600-JD, Akzo-Nobel) were homogenized in a ratio of 94:3 by weight, and
a PVDF binder solution was added thereto, producing a slurry containing
the active material, the carbon conducting agent and the PVDF binder
solution in a weight ratio of 94:3:3. The produced slurry was applied to
a 15 μm thick aluminum (Al) foil and dried to form a cathode plate,
followed by further drying in vacuum, thereby manufacturing a coin-type
cell to perform charge/discharge tests.

[0051]In the manufacture of the cell, lithium metal was used as a counter
electrode and 1.3 M LiPF6 in ethylene carbonate/diethylcarbonate
(EC:DEC, 3:7) was used as an electrolyte. Constant current charging was
performed at 20 mA/g and 4.55 V cut-off, constant voltage charging was
performed, and the charged state was maintained until the current dropped
to a level of approximately 2 mA/g. Constant current discharging was
performed at approximately 2 mA/g and 2 V cut-off. After the first two
cycles, the current density was raised to 75 mA/g and 50
charging/discharging cycles were repeated. The results of the
charge/discharge tests are shown in FIGS. 1 through 3.

COMPARATIVE EXAMPLE 2

[0052]An electrode was coated only with Al2O3-coated LiCoO2
(synthesized by the method disclosed in U.S. Pat. No. 6,753,111). An
active material and a carbon conducting agent (KETJENBLACK® EC600-JD)
were homogenized in a ratio of 94:3 by weight, and a PVDF binder solution
was added thereto, producing a slurry containing the active material, the
carbon conducting agent and the PVDF binder solution in a weight ratio of
94:3:3. The produced slurry was applied to a 15 μm thick Al foil and
dried to form a cathode plate, followed by further drying in vacuum,
thereby manufacturing a coin-type cell to perform charge/discharge tests.
In the manufacture of the cell, lithium metal was used as a counter
electrode and 1.3 M LiPF6 in EC:DEC (3:7) was used as an electrolyte.
Constant current charging was performed at 20 mA/g and 4.55 V cut-off,
constant voltage charging was performed and the charged state was
maintained until the current dropped to a level of approximately 2 mA/g.
Constant current discharging was performed at approximately 2 mA/g and 2
V cut-off. After the first two cycles, the current density was raised to
75 mA/g and 50 charging/discharging cycles were repeated. The results of
the charge/discharge tests are shown in FIGS. 1 through 3.

EXAMPLE 1

[0053]Sub-micron sized
Li1.2Ni0.133Co0.133Mn0.534O2, which was prepared
by combustion synthesis, and Al2O3-coated LiCoO2
(synthesized by a method disclosed in U.S. Pat. No. 6,753,111 and
commercially available), were mixed to be used to form a coating on an
electrode surface. The amount of LiCoO2 in the mixed active material
was fixed at a level of 30 wt %. Conditions of preparing electrodes and
cells, and charging/discharging conditions were the same as those in
Comparative Examples 1 and 2. The results of the charge/discharge tests
are shown in FIGS. 1 through 3.

EXAMPLE 2

[0054]Sub-micron sized
Li1.2Ni0.133Co0.133Mn0.534O2, which was prepared
by combustion synthesis, and Al2O3-coated LiCoO2, (the
commercially available product of Example 1), were mixed to be used to
form a coating on an electrode surface. The amount of LiCoO2 in the
mixed active material was fixed at a level of 40 wt %. Conditions of
preparing electrodes and cells, and charging/discharging conditions were
the same as those in Comparative Examples 1 and 2. The results of the
charge/discharge tests are shown in FIGS. 1 through 3.

EXAMPLE 3

[0055]Sub-micron sized
Li1.2Ni0.133Co0.133Mn0.534O2, which is prepared
by combustion synthesis, and Al2O3-coated LiCoO2, (the
commercially available product of Example 1), were mixed to be used to
form a coating on an electrode surface. The amount of LiCoO2 in the
mixed active material was fixed at a level of 50 wt %. Conditions of
preparing electrodes and cells, and charging/discharging conditions were
the same as those in Comparative Examples 1 and 2. The results of the
charge/discharge tests are shown in FIGS. 1 through 3.

EXAMPLE 4

[0056]Sub-micron sized
Li1.2Ni0.133Co0.133Mn0.534O2, which is prepared
by combustion synthesis and Al2O3-coated LiCoO2, (the
commercially available product of Example 1), were mixed to be used to
form a coating on an electrode surface. The amount of LiCoO2 in the
mixed active material was fixed at a level of 60 wt %. Conditions of
preparing electrodes and cells, and charging/discharging conditions were
made the same as those in Comparative Examples 1 and 2. The results of
the charge/discharge tests are shown in FIGS. 1 through 3.

[0057]FIG. 1 is a graph illustrating current density expressed as capacity
per weight (mAh/g) and capacity ratio as functions of various mixture
ratios of Li1.2Ni0.133Co0.133Mn0.534O2 and
Al2O3-coated LiCoO2 according to Examples 1 through 4 of
aspects of the present invention and Comparative Examples 1 and 2. FIG. 2
is a graph illustrating current density expressed as capacity per volume
(mAh/cc) as a function of various mixture ratios of
Li1.2Ni0.133Co0.133Mn0.534O2 and
Al2O3-coated LiCoO2 according to aspects of the present
invention and Comparative Examples 1 and 2.

[0058]As is evident from FIG. 1 the cathode active materials in Examples 1
through 4 of aspects of the present invention were superior to those in
Comparative Examples 1 and 2 from the viewpoints of both the capacity per
weight and the capacity per volume. The cathode active material in
Comparative Example 1, in which only
Li1.2Ni0.133Co0.133Mn0.534O2 was used, had a
good weight capacity but showed a noticeable reduction in the capacity
per volume. The cathode active material in Comparative Example 2, in
which only Al2O3-coated LiCoO2 was used, showed a
noticeable reduction in the capacity per weight while maintaining a
predetermined level of capacity per volume.

[0059]FIG. 3 illustrates the percentage of capacity retention after 50
cycles as a function of various mixture ratios of
Li1.2Ni0.133Co0.133Mn0.534O2 and
Al2O3-coated LiCoO2 according to Examples 1 through 4 of
aspects of the present invention and Comparative Examples 1 and 2. In
Examples 1 through 4, more than 70% of the initial capacity was
maintained after 50 cycles, suggesting that the cells of Examples 1
through 4 had commercially acceptable levels of capacity retention.

[0060]According to aspects of the present invention, a cathode is capable
of improved conductivity while maintaining a high capacity by adding a
lithium-containing compound having improved conductivity to an active
material composite. In particular, the life span can be enhanced by
improving high-voltage stability. A lithium battery employing the cathode
according to these aspects of the present invention allows for an easier
cell design relative to a counter electrode, thereby further increasing
commercial availability of a high-capacity cathode active material.

[0061]Although a few embodiments of the present invention have been shown
and described, it would be appreciated by those skilled in the art that
changes may be made in this embodiment without departing from the
principles and spirit of the invention, the scope of which is defined in
the claims and their equivalents.

Patent applications by Seok-Gwang Doo, Yongin-Si KR

Patent applications by Samsung SDI Co., Ltd.

Patent applications in class RADIO ACTIVE MATERIAL CONTAINING

Patent applications in all subclasses RADIO ACTIVE MATERIAL CONTAINING